Detachable propulsion mechanisms for boats



March 10, 1964 A. T. c. PRIDDLE 3,124,097

DETACHABLE PROPULSION MECHANISMS FOR BOATS Filed April 19, 1962 United States Patent 3,124,097 DETACHABLE PROPULSlQN MEilHANlSMS FQR BOATS Albert Thomas Claud Priddle, Twiclrenham, Middlesex, England, assignor to CAN. Limited, London, England Filed Apr, 19, 1962, Ser. No. 188,721 6 Qlairns. (Cl. 11517) This invention relates to detachable propulsion mechanism for boats of the kind comprising a unit adapted for detachable connection to a boat, the unit including an internal combustion engine, a propeller rotatable by the engine and means whereby the unit can be moved angularly relative to the boat to which it is connected to effect steering of the latter.

The object of the invention is to provide such a propulsion mechanism in a convenient and efiicient form.

According to the invention in a propulsion mechanism of the kind specified the internal combustion engine is of the compression ignition type having a cylinder block and crank-case which are arranged to be totally submerged below water level when the mechanism is in normal use.

In the accompanying drawing an example of the invention is illustrated in sectional side elevation.

Referring to the drawing the lower part of the unit includes a cylinder block 1 and a crankcase 2 of a single cylinder two-stroke compression ignition engine which under normal working conditions is intended to be totally submerged within the water, the normal water level being indicated by the line x*x. A crankshaft 3 of the engine extends from one end of the crankcase 2 and has a propeller 4 mounted upon it. The outer ends of the blades 4? of this propeller are interconnected by an integral annular rim 4 which is streamlined in an axial direction and is of suflicient mass to cause the propeller to act also as a flywheel for the engine. Moreover, the underside of the crankcase is shaped to form an integral skeg 2 Within the end of the crankcase 2 remote from the propeller is defined a sump 2 from which lubricating oil can be drawn at timed intervals into the portion 2 of the crankcase below the piston 5 through a pair of cooperating passages 6, 6 in the crankcase and crankshaft respectively, these passages being in register once during each revolution of the crankshaft, at a time when a depression exists below the piston 5. Also formed on the adjacent parts of the crankcase and cylinder block is the usual form of transfer port 7, whilst in the cylinder block is formed an exhaust port 8 which at its outer end opens upwardly.

A hollow intermediate part of the unit connected to the upper side of the cylinder block 1 constitutes a fuel tank 9 and within the lower end of this fuel tank is an injection pump 10 which is also secured to the cylinder block. The injection pump includes a fuel inlet filter i1 and is adapted to be actuated through a push rod 12 from a cam 13 on a portion of the crankshaft extending into the sump 2 Moreover the pump 10 is adapted to deliver fuel from the fuel tank in which it is immersed, to an injection nozzle 14 located in a combustion chamber opening into the cylinder l of the engine.

To the upper end of the fuel tank 9 is secured a hollow body part 15 which is mounted for swivelling movement within a collar 16 pivoted on a bracket 17 whereby the unit can be clamped to the stern board 18 of a boat in the normal manner of an outboard motor. Moreover, the collar 16 may carry a catch piece 19 engageable with a pin 2.8 in the bracket to retain the propeller 4 out of the water when the unit moves angularly in the bracket.

The body part 15 has a laterally extending arm 21 which serves as a tiller and which at its outer end carries 3,l2l,@97 Patented Mar. 10, 1964 a twist-grip throttle control 22 connected to a lever 23 at the inner end of the arm. The lever is connected by a link 24 extending downwardly through the fuel tank to an angularly movable arm 25 on the injection pump for varying the quantity of fuel supplied to the engine, and thereby the speed of the engine.

The body part 15 is divided internally to form two passages, one of which serves as a filling neck for the fuel tank 9 and is closable by a detachable screw-threaded cover 26, and the other of which serves as the filling neck for the sump 2 and also as the combustion air inlet. The latter passage has connected to its lower end a tube 27 which extends downwardly through the fuel tank 9 into the cylinder block 1 above the sump 2 Moreover, above the oil level there is formed in the cylinder block a port 28 through which combustion air can enter the cylinder below the piston when the latter is at the upper end of its stroke.

Extending through the tube 27 is a flexible cord 29 which at its lower end is connected to a spiral spring tape 3% connected to a uni-directional clutch surrounding the end of the crankshaft 3 within the sump 2 The upper end of the cord 29 is connected to a handle 31 which is shaped to form a cover for the associated filling neck, and the arrangement is such that by pulling on the handle 31 to unwind the spring 30 the crankshaft can be rotated for starting the engine. However, when the handle is released the spiral spring will re-assert itself as permitted by the clutch to return the handle to its position on the outer end of the filling ne k in readiness for the next starting operation. Desirably a roller 32 is provided in the sump filling neck to serve as a guide for the flexible cord 2? when the handle is pulled by an individual standing to one side of the unit as would happen when the individual is within a boat on which the unit is mounted.

Secured to the outer end of the aforesaid exhaust port 8 is a vertical exhaust pipe 33 which extends to a position which will be well above the water level xx when the mechanism is-operating under normal conditions, and surrounding this exhaust pipe in spaced relationship is a hollow bell-shaped silencer casing 34 the open lower end of which is disposed to be slightly below the water level x-x under normal operating conditions. Thus exhaust gases are caused to flow upwardly through the exhaust pipe and then downwardly through the silencer casing and to be discharged below the Water level, thereby effecting efficient silencing of the engine.

It will be understood that steering of the boat can be effected by angular movement of the unit constituted by the body part 15, fuel tank 9*, cylinder block ll, crankcase 2 and the propeller 4 relative to the boat.

Although the invention has been described in its application to a mechanism which is adapted to be mounted outboard, it will be appreciated that it is also applicable to a mechanism which is adapted to be mounted inboard with the lower part of the unit constituted by the cylinder block, crankcase and propeller, extending below the bottom of the boat.

By the present invention a particularly compact and convenient construction of propulsion mechanism is provided, and by virtue of the fact that under normal working conditions the cylinder block and crankcase are totally immersed within the water cooling of the engine is greatly facilitated.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. For use in propelling and steering a boat, a unitary propulsion mechanism adapted for detachable connection to the boat, and comprising in combination a compression ignition internal combustion engine which is totally submersible below water level when the propulsion mech- 3 anisin is in normal use, and which has a cylinder block, a crankcase at the underside of said cylinder block, a piston slidably mounted in said cylinder block so as to be movable towards and away from the upper portion of said cylinder block, and a fuel injection nozzle which communicates with the interior of said cylinder block at a position above said piston, an oil sump in said crankcase at one end thereof, a crankshaft which is operatively connected to said piston, and which is rotatably supported in said crankcase with one end portion of said crankshaft extending into said oil sump, and the opposite end portion of said crankshaft extending outwardly from the end of said crankcase remote from said oil sump, a propeller mounted on the last mentioned end portion of said crankshaft, a fuel tank secured to, and extending upwardly from, the upper portion of said cylinder block, an injection pump which is mounted within the lower end of said fuel tank, and which is adapted to deliver fuel from said fuel tank to said fuel injection nozzle, a cam on the portion of said crankshaft within said oil sump, means for actuating said injection pump under the action of said cam, a hollow body part secured to the upper end of said fuel tank, and means which are connected to said hollow body part, and through the medium of which the unitary propulsion mechanism is detachably connectable to the boat.

2. A unitary propulsion mechanism according to claim 1, wherein said means which are connected to said hollow body part comprise in combination a bracket detachably connectable to the boat, and a collar in which said hollow body part is rotatably mounted, and which is pivotably connected to said bracket.

3. A unitary propulsion mechanism according to claim 1, wherein said hollow body part is divided internally to form a pair of filling necks one of which communicates with the upper end of said fuel tank, and the other of which has connected thereto a tube extending through said fuel tank and communicating with said oil sump.

4. A unitary propulsion mechanism according to claim 1, wherein said compression ignition internal combustion engine has a longitudinal transfer port formed in adjacent parts of said cylinder block and said crankcase.

5. A unitary propulsion mechanism according to claim 1, wherein said propeller comprises a plurality of radial blades, and an annular rim integral with, and interconnecting the outer ends of, said blades, so that said propeller also serves as a fly-wheel.

6. A unitary propulsion mechanism according to claim 1, wherein said crankcase and said crankshaft are provided respectively with a pair of passages which, during each revolution of said crankshaft, register once with each other for admitting oil from said oil sump to the interior of said cylinder block at a position below said piston.

References Cited in the file of this patent UNITED STATES PATENTS 1,446,775 Wahl Feb. 27, 1923 2,235,140 Clarke Mar. 18, 194l FOREIGN PATENTS 940,628 Germany Mar. 22, 1956 

1. FOR USE IN PROPELLING AND STEERING A BOAT, A UNITARY PROPULSION MECHANISM ADAPTED FOR DETACHABLE CONNECTION TO THE BOAT, AND COMPRISING IN COMBINATION A COMPRESSION IGNITION INTERNAL COMBUSTION ENGINE WHICH IS TOTALLY SUBMERSIBLE BELOW WATER LEVEL WHEN THE PROPULSION MECHANISM IS IN NORMAL USE, AND WHICH HAS A CYLINDER BLOCK, A CRANKCASE AT THE UNDERSIDE OF SAID CYLINDER BLOCK, A PISTON SLIDABLY MOUNTED IN SAID CYLINDER BLOCK SO AS TO BE MOVABLE TOWARDS AND AWAY FROM THE UPPER PORTION OF SAID CYLINDER BLOCK, AND A FUEL INJECTION NOZZLE WHICH COMMUNICATES WITH THE INTERIOR OF SAID CYLINDER BLOCK AT A POSITION ABOVE SAID PISTON, AN OIL SUMP IN SAID CRANKCASE AT ONE END THEREOF, A CRANKSHAFT WHICH IS OPERATIVELY CONNECTED TO SAID PISTON, AND WHICH IS ROTATABLY SUPPORTED IN SAID CRANKCASE WITH ONE END PORTION OF SAID CRANKSHAFT EXTENDING INTO SAID OIL SUMP, AND THE OPPOSITE END PORTION OF SAID CRANKSHAFT EXTENDING OUTWARDLY FROM THE END OF SAID CRANKCASE REMOTE FROM SAID OIL SUMP, A PROPELLER MOUNTED ON THE LAST MENTIONED END PORTION OF SAID CRANKSHAFT, A FUEL TANK SECURED TO, AND EXTENDING UPWARD- 